Portable surfacing machine



March 12, 1940. E. B; GEORGE 293419 4 PORTABLE suRFAcING MAcHmE Filed.June 27; 1938 ATTORNEY. r

Patented Mar. l2, 1940 UNITED STATES PATENT. OFFICE ron'rmn sUarAcmamoms Edward B. George, Chica-ign, lll.

Appueeaon June ai, 193s. serial No. 216,004 s claims. (ci. :s1-rw) Thisinvention pertains to surfacing machines of the portable type adaptedfor smoothing and finishing flat surfaces of wood or other material.

One of the purposes of my present -invention is to provide a machine ofthis character havinga speed reducing gearing between the electricrnotor andthe surfacing pad which will enable a relatively small motorto be used without danger of stalling the same if the operator shouldapply more than the requisite or .usuali amount of pressure to the tool.

Another object is to provide a. construction by which an accurateadjustment of the relative positions of the meshing gears may beattained by a simple adjustment made during the assembly ofthe apparatusand the provision of means for thereafter holding the gears againstdisplacement from such adjusted position.

A further purpose is to provide a exible connection of novelconstruction between the motor frame and the surfacing pad which willabsorb vibrations and permit the pad to rest atly upon kthe surfacebeing treated irrespective of tilting movements of the motor frame.'

Another feature of the invention resides in a construction which permitsthe direct application of any desired amount of pressure from the motorframe to the pad without interfering with the operation of the drivingmechanism.

A further feature is found inthe novel means employed for protecting theoperating parts against grit particles and dust which cause rapid wearof the parts.

Still another feature'of novelty resides the structure by which thecovering sheet for the pad is detachably secured in position.

Other objects and advantages of my invention will be readily appreciatedas lthe same becomes better understood by reference to the followingdescription when considered in connection with the accompanying drawing.

Referring to the drawing,

Fig. 1 is a vertical sectional view of a machine 'i embodying myinvention, the upper portion being shown in. elevation:

' Fig. 2 is a sectional view ontheline 1 2 of Fig. 1:

A Fig. 3 is a sectional view on the line 3--3 of Fig. 1; and

Fig. 4 is a sectional view on the line l--I of Fig. 1. i

Referring to the drawing more in detail, ref-y' erence character 5indicates the motorbase of the'ma'chine4 provided with an annularshoulder tover which rotatably ilts an adjusting sleeve 1 provided atits lower end with an eccentrically disposed annular 'shoulder 8surrounding the shoulder 6 and at its upper end with a concentricannular shoulder 9. surrounding therdepending concentric annularshoulder il of the motor 5 motor case is equipped at itsv lower-end witha ,u

driving pinion il.

The upper face ofthe base 5 is recessedv to accommodate a ball-bearingi8 and the lower face is similarly recessed to receive anotherVballbearing i9,.each bearing comprising the inner .and outer races andinterposed balls as is usual 'in bearings of this type. g A shaft'20journaled in these bearings has xedly mounted upon its upper endaninternalgear 2l adapted to mesh with the pinionV I1 and has threadedupon its lower portion a nut 22 which, through an interposed washer 23,holds'the bearings and sha-ft against displacement relatively to themotor base.

In order to insurevproper driving relation between the pinion l1 and thegear 2|, which will 8 enable these gears to run quietly and withoutundue wear, relative adjustment between these gears is provided by theadjusting sleeve 1 previously described. When the parts arebeingassembled, the,gear adjustment is effected by ro- 95 tation of thissleeve. Since the recess in the upper end of the sleeve surrounding theshoulderv ii is concentric with-the motor shaft and, therefore, with thepinion i1,"and the recess in its lower end surrounding the shoulder 6 ofthe base 40 5in which the shaft 20 carrying the internal gear 2| .ismounted is eccentric to the motor shaft, rotationof the sleeve 1 betweenvthe motor and its base will move the base in a straight. linerelatively to the motor, thereby causing the gear 45 2i to approach orrecede from pinion Il until the requisite relative positions of theseinterj meshing parts is attained., The downwardly disposed shoulder ofsleeve 1 is provided with a series of closely positioned tapped openingsfor the re- 50 ception of the cap screws 24 extending throughopenings'inthe base 5. When proper adjustment of the gears has beensecured, these cap screws are inserted and threaded home, therebylocking the base and sleeve together with thek Il gears in properrelation. The sleeve may be locked to the motor housing by any preferredmeans, such as one or more set screws (not shown) extending through thesleeve into engagement with the shoulder Il.

The lower end of shaft has fixed thereto by a'set screw 25, orotherwise, a lcrank arm 26 carrying a depending crank pin 21 upon whichis snugly fitted the inner race 28 of a ball-bearing including the outerrace 2.5i and the interposed balls 3|. Atransverselydisposed opentopguide,- way 32v is fixed tothe pad plate 33 and proportioned to looselyreceive the 'outer race 29, the perimeter of which is curved on avertical arc so as to provide a line contact withthe'sides of theguideway and permit tilting movements of the motor relative to the padplate without'imposing strains upon the driving mechanism. 'The lowerend 34 of the crank pin 211 is roundedasv shown, and hardened to providea thrust surface against the opposed hardened bottom wall of, the fguideway, so that downward pressure -exerted upon the motor housingrectly to the pad.`

The pad plate is flexibly connected motor. base through a` pair offlexible U-shaped members 35 and 36 rigidly secured by bolts or iotherwise to the pad and to the base. These members, preferably offibrous composition, possess sufiicient resiliency to normally supportthe weight of the motor with the thrust end 34 of the crank pin freefrom contact with the bottom of the guide member 32. 'Ihe apparatus maybe operated, therefore, merely with the weight of the motor Iapplied tothe pa'd, but if additional pressure is desired, as is customary, suchpressure exerted by the operator is transmitted directly through thecrank pin to the pad plate. 'Ihe pressure thrust is, therefore, not,transmitted to the pad through the flexible members 35 and 36, with theresult that their resiliency and consequently rigidity is not increasedand they are free to absorb the vibrations ofthe pad and prevent theirtransmission to the motor case.

This construction provides a smoother running machine and one freer fromvibration than those in which pressure is applied to thepad. through anyflexible connection, the rigidity of which varies with the amount ofpressure applied.

'I'he pad itself, indicated by reference character 31, may be of anysuitable resilient material attached to the plate 33, and the workingface thereof is covered by a detachable covering such as sandpaper,emery cloth, or other fabric 38 which in the present instance islaidover the surface of the pad and its ends brought around the up-turnedloops 39 and 4I of the plate. For the purpose of detachably holding thesheet 38 in. position, I employ a rectangular holding member 42 formedof resilient wire provided at one end with a roller 43. In applying theholder, the lefthand end viewing Fig. 1 is positioned at the base of theloop 4|, whereupon the 'other end is rolled down to the base of loop 39into the position shown. The resiliency of the holder clamps the fabricbetween its ends and the bases of the loops, thereby securely holdingthe sheet in position.

In order to protect the driving mechanism from the abrasive effect `ofdust and otherparticlesv produced by the operation of the machine, Ihaveprovided a boot 44, secured at its lower end around the guide 32,` andhaving its upper end in-tu'rned, 'as shown in Fig'. 1, and clamped tothe maybe transmitted di- I with "the within considerable limits withoutdeparting from the essence of the invention as set forth in thefollowing claims.y

Iclaim: i A, 1. In a surfacing machine, the combination of a'.v motor, asurfacing pad, a motor base flexibly connected to said pad, a drivingshaft journaled that the structural details thereof may be varied insaidbase, driving connections between one end of said shaft and saidpad, a gear wheel mounted p on the other end of said shaft, a motorshaft provided with a` pinion meshing with said gear Wheel, andanadjustable connection between the motor and said motor base whereby therelative position of said gear wheel and pinion may be adjusted. i

- 2. In a surfacing machine, the combination of a motor, a gear wheelfixed on the motor shaft,

a motor base, a shaft journaled in said base, agear .wheel fixed on saidshaft and meshing with said first mentioned gear wheel, and anadjustable connection between said motor and said base for adjusting therelative positions of said gear wheels.

3. In a surfacing machine, the combination of a motor, a driving pinionon the motor shaft, a motor base, a shaft journaled therein, a gearwheel mounted on said last mentioned shaft, and an adjusting sleeveinterposed between said motor and said base, said sleeve. beingconcentrically associated with the motor and eccentrically associatedwith the base to provide for relative adjustment between said pinion andgear wheel. 4

4. In a surfacing machine, the'cornbination of a motor, a pinion on themotor shaft, an adjusting sleeve rotatable concentrically with the motorshaft', a motor base rotatably associated with said sleeve and arrangedeccentrically whereby rotation of saidsleeve will effect a transverseadjustment between the motor and said base, a`

shaft mounted in the base, a gear wheel on the shaft adapted t'o meshwith said pinion, a surfacing pad, and driving connections between saidshaft and said pad.

5. In a surfacing machine, the combination of a surfacing pad, anupwardly opening guideway connected to said pad, a motor driven shaftprovided at'its lower end with a crank pin disposed in said guideway,the lower end of said pin being tapered to ride upon the bottom of saidguideway upon the lapplication of downward pressure upon said shaft, amotor connected with the shaft,

and flexible connections between the motor and l said pad, saidconnections being adapted to yield under downward pressure topermitthrust to be exerted upon the pad through said shaft.

6. In a surfacing machine, the combination of a pad provided with anupwardly opening guideway, a motor base, a shaft mounted in said baseand provided at its lower end with a crank pin disposed in saidguideway, a motor mounted vupon said' base and operatively connectedwith said shaft, and resilient connections between the motor base' andsaid pad. said connections being adapted to sustain 'the weight of themotor but to yield under downward pressure exerted upon the motor. topermit the transmission of said pressure to the pad through said crankpin.

7. In a surfacing machine, the combination of Aa motor base having avertically disposed shaft rotatably mounted therein, a motor carried bythe base and operatively connected with said shaft, a

crank pin mounted on the lower end of said shaft,`

a guide member into which said pinextends, a surfacing pad associatedwith said guideway to be actuated thereby upon rotation of said shaft,and a pair of U-shaped resilient connections between the pad and themotor base adapted to sustain the weight of the motor but adapted toyield under downward pressure exerted upon'the motor to permit thetransmission of said pressurethrough said shaft and crank pin to saidpad.

8. In' a 'surfacing machine, the combination of a surfacing pad, aguideway connected to said pad, a motor driven shaft provided at itslower end with a crank pin disposed in said guideway.

and adapted to engage the bottom of said guideway upon the applicationof downward pressure upon said shaft, a motor connected with the shaftand exible connections between the motor and pad adapted to yield underdownward pressure so as to enable exertion of thrust upon the padthrough said shaft.

EDWARD B. GEORGE.

